Heater not hot enough?
Ok, we all know that convertibles such as the Lotus Elise and Elan can be very cold during the winter months with the roof down. So what can we do about it? The main problem with most rag tops is hot air in the cabin being scooped out by wind turbulence and back wash. The back wash is the air flowing over the top of the car and washed back across the engine lid at the rear into the cabin. This why some spider type convertibles have a wind break behind the seats, in the case of the Elise, the rear glass window. So the Elise, the main problem is the lack of air outlets that most cars have on the dash for the driver and passenger. The Elise only has foot well and windscreen outlets, with a heater matrix which handles roof-on heating fine but roof-off driving, it struggles. This is where we come back to the air backwash scooping out hot air, even with the rear window in. In cold conditions you will probably notice this by a cold left shoulder (in a right hand drive car).
What are the options to improve yours? We can start with your heater control set up. In over three years of ownership, I have found that once you have de-misted the windscreen, the heater temperature control should obviously be set to full, and then move the direction control to slightly left of center (S1) so you are set the bias towards the foot well. Also opening the four windscreen hatches with the center ones pointing at you and the outer ones slightly towards the side door windows. A point to note out of kindness if you've never been a passenger in an Elise, it's colder on that side due to the outlet under the dash being bias to the driver, not so much on the S2 mind. So you may wish to close the driver side windscreen hatches. You can gain even more heat by removing the rear window on the Elise S1. The reason for this is down to the wind backwash sweeping over the engine lid air vents and picking up the rising hot air from the engine. To see how to remove the window and take it with you, see the Spiderising the Elise article.
An extra add-on solution are the plug-in heaters that you find in gadget catalogues such as the Innovations magazine that sometimes comes through the letter box. I haven't personally tested one of these units, but there recently was a thread in the British Cars BBS discussing these products. The units plug into the lighter socket, and is placed where you want the heat, but the general feeling was that they are not powerful enough in an open-top environment to make a difference and not worth while of the cost, space and weight. Some even suggested that the power used by these units do not match anywhere near that of the cars own heater matrix and so no version of these types of heater will be of use in this type of application. There has also been some talk recently about interchanging heater matrix components, especially between the S1 and S2 Elise (for improved S2 heating), but I have no confirmation if this is possible.
Finally it would be nice for the passenger of an S1 Elise to have a replacement outlet in the foot well to split the hot air either side. I don't know if this would make much difference, it has already been addressed in the S2, but may be this would be a project for www.hangar111.com, maybe making more sense if it pointed towards the back of the car rather than at the feet, or even directional to suit your own preference.
This was written during the winter, but even in places such as the UK, it can be just as relevant for late summer nights. So, it looks like apart from taking the rear window out, it's hat, coat and gloves.
Craig D.r. 26th June 2003
w. 23.01.03